Locking device



FIG. 1 is a rear view of a locking device in my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom perspective view thereof.

The broken lines shown in the locking device are for portions that form no part of the claimed design. 

CLAIM The ornamental design for a locking device, as shown and described. 